The present invention relates to a catheter intended for implantation within a living body for long term usage, and more particularly to an implantable single lumen catheter having a bidirectional check valve for controlling fluid flow into and out of the catheter.
Various medical procedures require vascular access over a period of time. Such procedures may include implantation of a permanent intravascular device for portable drug infusion devices, for hemodialysis, or for cases where continuous blood work or access to the bloodstream is required. These procedures are often performed by using either transcutaneous or totally implanted catheters and fluid access devices.
There are problems associated with long term catheterization of a blood vessel. A first problem is infection at the skin puncture point, and a second problem is clotting of blood within the catheter lumen. The first problem may be solved by installing a subcutaneous fluid access assembly in a patient and which is coupled to the patient's bloodstream by means of an implanted catheter As for the second problem, in cases where the flow rate of the fluid carried by the catheter is very high, or perhaps if an anti-coagulant is carried by the fluid in the catheter, then the catheter will remain open to fluid flow over the long term. However, in situations with low fluid flow rates, or only intermittent fluid flow, clots or plugs may form inside of the catheter lumen, thus obstructing fluid flow. This limits the useful lifetime of the implanted catheter, or requires constant flushing or heparinization.
It has also been experienced that changes in blood pressure may cause a fluctuating pressure at the tip of an implanted catheter. Such fluctuation can induce a backflow of blood up the catheter. This blood is subject to clotting.
A known commercially available bidirectional check valve catheter features a slit valve. The tip of the catheter is closed and the side wall of the catheter near the tip is slit, to form the slit valve. The valve allows both aspiration of blood and infusion of fluids. The check valve precludes the diffusion of blood into the lumen when the catheter is not in use. This catheter is known as the Groshong catheter (available from Catheter Technology Corporation, Salt Lake City, Utah).
While various other valved catheters are also known, there is still a need for an improved implantable, bidirectional check valve catheter assembly with long useful life, which does not require special maintenance, and with low potential of formation of obstructions, such as emboli.
It is therefore an object of the present invention to provide an implantable catheter with a long useful life and which does not require special maintenance.
It is another object of the present invention to provide a check valve catheter which is resistant to occlusion from blood clot, and does not require heparinization.
It is yet another object of the present invention to provide an intravascular catheter with a bidirectional check valve which permits long term placement in the bloodstream without requiring flushing to keep the catheter lumen fluid flow path open.